1. Field of the Invention
This invention relates to a method for folding an envelope-shape jacket material for a magnetic cartridge.
2. Description of the Prior Art
In recent years, a magnetic cartridge with a magnetic disk on which voice signals, video signals, data signals, etc. are recorded and which is enclosed in an envelope-shape jacket has been used practically. The magnetic cartridge of this type is inserted into a floppy disk device of a computer as the magnetic disk therefor, while enclosed in a jacket and the recorded signal is reproduced by rotating the magnetic disk and by making a reproduction head follow the track thereon.
In the conventional method of folding jacket material, a forward end of a folding bar is positioned at the end surface of a table and the folding bar is simply moved in an arc and therefore loosening, warping, waving, swelling, etc. are liable to take place at the folded edge and as a heater bar is applied to such folded edge so that, formation of the folded edge is inaccurate, with the result of poor external shape and poor dimensional precision of the jacket.